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linux/drivers/iio/adc/mcp320x.c
Søren Andersen b12206e917 iio: adc: mcp320x. Add support for more ADCs 
Signed-off-by: Soeren Andersen <san at rosetechnology.dk>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-10-09 20:14:03 +01:00

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9.1 KiB
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/*
* Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
* Copyright (C) 2014 Rose Technology
* Allan Bendorff Jensen <abj@rosetechnology.dk>
* Soren Andersen <san@rosetechnology.dk>
*
* Driver for following ADC chips from Microchip Technology's:
* 10 Bit converter
* MCP3001
* MCP3002
* MCP3004
* MCP3008
* ------------
* 12 bit converter
* MCP3201
* MCP3202
* MCP3204
* MCP3208
* ------------
*
* Datasheet can be found here:
* http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf mcp3001
* http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf mcp3002
* http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf mcp3004/08
* http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf mcp3201
* http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf mcp3202
* http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf mcp3204/08
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/regulator/consumer.h>
enum {
mcp3001,
mcp3002,
mcp3004,
mcp3008,
mcp3201,
mcp3202,
mcp3204,
mcp3208,
};
struct mcp320x_chip_info {
const struct iio_chan_spec *channels;
unsigned int num_channels;
unsigned int resolution;
};
struct mcp320x {
struct spi_device *spi;
struct spi_message msg;
struct spi_transfer transfer[2];
u8 tx_buf;
u8 rx_buf[2];
struct regulator *reg;
struct mutex lock;
const struct mcp320x_chip_info *chip_info;
};
static int mcp320x_channel_to_tx_data(int device_index,
const unsigned int channel, bool differential)
{
int start_bit = 1;
switch (device_index) {
case mcp3001:
case mcp3201:
return 0;
case mcp3002:
case mcp3202:
return ((start_bit << 4) | (!differential << 3) |
(channel << 2));
case mcp3004:
case mcp3204:
case mcp3008:
case mcp3208:
return ((start_bit << 6) | (!differential << 5) |
(channel << 2));
default:
return -EINVAL;
}
}
static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
bool differential, int device_index)
{
int ret;
adc->rx_buf[0] = 0;
adc->rx_buf[1] = 0;
adc->tx_buf = mcp320x_channel_to_tx_data(device_index,
channel, differential);
if (device_index != mcp3001 && device_index != mcp3201) {
ret = spi_sync(adc->spi, &adc->msg);
if (ret < 0)
return ret;
} else {
ret = spi_read(adc->spi, &adc->rx_buf, sizeof(adc->rx_buf));
if (ret < 0)
return ret;
}
switch (device_index) {
case mcp3001:
return (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
case mcp3002:
case mcp3004:
case mcp3008:
return (adc->rx_buf[0] << 2 | adc->rx_buf[1] >> 6);
case mcp3201:
return (adc->rx_buf[0] << 7 | adc->rx_buf[1] >> 1);
case mcp3202:
case mcp3204:
case mcp3208:
return (adc->rx_buf[0] << 4 | adc->rx_buf[1] >> 4);
default:
return -EINVAL;
}
}
static int mcp320x_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *channel, int *val,
int *val2, long mask)
{
struct mcp320x *adc = iio_priv(indio_dev);
int ret = -EINVAL;
int device_index = 0;
mutex_lock(&adc->lock);
device_index = spi_get_device_id(adc->spi)->driver_data;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = mcp320x_adc_conversion(adc, channel->address,
channel->differential, device_index);
if (ret < 0)
goto out;
*val = ret;
ret = IIO_VAL_INT;
break;
case IIO_CHAN_INFO_SCALE:
ret = regulator_get_voltage(adc->reg);
if (ret < 0)
goto out;
/* convert regulator output voltage to mV */
*val = ret / 1000;
*val2 = adc->chip_info->resolution;
ret = IIO_VAL_FRACTIONAL_LOG2;
break;
}
out:
mutex_unlock(&adc->lock);
return ret;
}
#define MCP320X_VOLTAGE_CHANNEL(num) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (num), \
.address = (num), \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
}
#define MCP320X_VOLTAGE_CHANNEL_DIFF(num) \
{ \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = (num * 2), \
.channel2 = (num * 2 + 1), \
.address = (num * 2), \
.differential = 1, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
}
static const struct iio_chan_spec mcp3201_channels[] = {
MCP320X_VOLTAGE_CHANNEL_DIFF(0),
};
static const struct iio_chan_spec mcp3202_channels[] = {
MCP320X_VOLTAGE_CHANNEL(0),
MCP320X_VOLTAGE_CHANNEL(1),
MCP320X_VOLTAGE_CHANNEL_DIFF(0),
};
static const struct iio_chan_spec mcp3204_channels[] = {
MCP320X_VOLTAGE_CHANNEL(0),
MCP320X_VOLTAGE_CHANNEL(1),
MCP320X_VOLTAGE_CHANNEL(2),
MCP320X_VOLTAGE_CHANNEL(3),
MCP320X_VOLTAGE_CHANNEL_DIFF(0),
MCP320X_VOLTAGE_CHANNEL_DIFF(1),
};
static const struct iio_chan_spec mcp3208_channels[] = {
MCP320X_VOLTAGE_CHANNEL(0),
MCP320X_VOLTAGE_CHANNEL(1),
MCP320X_VOLTAGE_CHANNEL(2),
MCP320X_VOLTAGE_CHANNEL(3),
MCP320X_VOLTAGE_CHANNEL(4),
MCP320X_VOLTAGE_CHANNEL(5),
MCP320X_VOLTAGE_CHANNEL(6),
MCP320X_VOLTAGE_CHANNEL(7),
MCP320X_VOLTAGE_CHANNEL_DIFF(0),
MCP320X_VOLTAGE_CHANNEL_DIFF(1),
MCP320X_VOLTAGE_CHANNEL_DIFF(2),
MCP320X_VOLTAGE_CHANNEL_DIFF(3),
};
static const struct iio_info mcp320x_info = {
.read_raw = mcp320x_read_raw,
.driver_module = THIS_MODULE,
};
static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
[mcp3001] = {
.channels = mcp3201_channels,
.num_channels = ARRAY_SIZE(mcp3201_channels),
.resolution = 10
},
[mcp3002] = {
.channels = mcp3202_channels,
.num_channels = ARRAY_SIZE(mcp3202_channels),
.resolution = 10
},
[mcp3004] = {
.channels = mcp3204_channels,
.num_channels = ARRAY_SIZE(mcp3204_channels),
.resolution = 10
},
[mcp3008] = {
.channels = mcp3208_channels,
.num_channels = ARRAY_SIZE(mcp3208_channels),
.resolution = 10
},
[mcp3201] = {
.channels = mcp3201_channels,
.num_channels = ARRAY_SIZE(mcp3201_channels),
.resolution = 12
},
[mcp3202] = {
.channels = mcp3202_channels,
.num_channels = ARRAY_SIZE(mcp3202_channels),
.resolution = 12
},
[mcp3204] = {
.channels = mcp3204_channels,
.num_channels = ARRAY_SIZE(mcp3204_channels),
.resolution = 12
},
[mcp3208] = {
.channels = mcp3208_channels,
.num_channels = ARRAY_SIZE(mcp3208_channels),
.resolution = 12
},
};
static int mcp320x_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
struct mcp320x *adc;
const struct mcp320x_chip_info *chip_info;
int ret;
indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
if (!indio_dev)
return -ENOMEM;
adc = iio_priv(indio_dev);
adc->spi = spi;
indio_dev->dev.parent = &spi->dev;
indio_dev->name = spi_get_device_id(spi)->name;
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &mcp320x_info;
chip_info = &mcp320x_chip_infos[spi_get_device_id(spi)->driver_data];
indio_dev->channels = chip_info->channels;
indio_dev->num_channels = chip_info->num_channels;
adc->transfer[0].tx_buf = &adc->tx_buf;
adc->transfer[0].len = sizeof(adc->tx_buf);
adc->transfer[1].rx_buf = adc->rx_buf;
adc->transfer[1].len = sizeof(adc->rx_buf);
spi_message_init_with_transfers(&adc->msg, adc->transfer,
ARRAY_SIZE(adc->transfer));
adc->reg = devm_regulator_get(&spi->dev, "vref");
if (IS_ERR(adc->reg))
return PTR_ERR(adc->reg);
ret = regulator_enable(adc->reg);
if (ret < 0)
return ret;
mutex_init(&adc->lock);
ret = iio_device_register(indio_dev);
if (ret < 0)
goto reg_disable;
return 0;
reg_disable:
regulator_disable(adc->reg);
return ret;
}
static int mcp320x_remove(struct spi_device *spi)
{
struct iio_dev *indio_dev = spi_get_drvdata(spi);
struct mcp320x *adc = iio_priv(indio_dev);
iio_device_unregister(indio_dev);
regulator_disable(adc->reg);
return 0;
}
#if defined(CONFIG_OF)
static const struct of_device_id mcp320x_dt_ids[] = {
{
.compatible = "mcp3001",
.data = &mcp320x_chip_infos[mcp3001],
}, {
.compatible = "mcp3002",
.data = &mcp320x_chip_infos[mcp3002],
}, {
.compatible = "mcp3004",
.data = &mcp320x_chip_infos[mcp3004],
}, {
.compatible = "mcp3008",
.data = &mcp320x_chip_infos[mcp3008],
}, {
.compatible = "mcp3201",
.data = &mcp320x_chip_infos[mcp3201],
}, {
.compatible = "mcp3202",
.data = &mcp320x_chip_infos[mcp3202],
}, {
.compatible = "mcp3204",
.data = &mcp320x_chip_infos[mcp3204],
}, {
.compatible = "mcp3208",
.data = &mcp320x_chip_infos[mcp3208],
}, {
}
};
MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
#endif
static const struct spi_device_id mcp320x_id[] = {
{ "mcp3001", mcp3001 },
{ "mcp3002", mcp3002 },
{ "mcp3004", mcp3004 },
{ "mcp3008", mcp3008 },
{ "mcp3201", mcp3201 },
{ "mcp3202", mcp3202 },
{ "mcp3204", mcp3204 },
{ "mcp3208", mcp3208 },
{ }
};
MODULE_DEVICE_TABLE(spi, mcp320x_id);
static struct spi_driver mcp320x_driver = {
.driver = {
.name = "mcp320x",
.owner = THIS_MODULE,
},
.probe = mcp320x_probe,
.remove = mcp320x_remove,
.id_table = mcp320x_id,
};
module_spi_driver(mcp320x_driver);
MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08");
MODULE_LICENSE("GPL v2");
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